neonatal jaundice some information

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Facts About Jaundice

Most jaundice in newborn babies is a normal event and is not serious. In most cases, this jaundice will disappear after a few days, often without any special treatment. Also, once this type of jaundice disappears, there is no evidence that it will appear again or that it has any lasting effects on the baby.

What does the word "jaundice" mean?
Jaundice comes from the French word jaune, which means yellow. When it is said that a baby is jaundiced, it simply means that the color of his skin appears yellow. Jaundice in the infant appears first in the face and upper body and progresses downward toward the toes. Premature infants are more likely to develop jaundice than full-term babies.

What causes the skin to appear yellow?
The yellowish coloration is caused by an excess amount of bilirubin in the baby's skin. Bilirubin is a yellowish-red pigment. Normally, small amounts of bilirubin are found in everyone's blood. When too much bilirubin is made, the excess is dumped into the bloodstream and is deposited in tissues for temporary storage.

Why would a baby have excess bilirubin in his blood?
Bilirubin is formed and released into the bloodstream when red blood cells are broken down. Newborns have a high red blood cell volume; this increases the bilirubin load. The bilirubin is then carried to the liver where it is processed and eventually excreted from the body.

Commonly, neonatal jaundice occurs for two reasons:

1. Infants have too many red blood cells. It is a natural process for the baby's body to break down these excess red blood cells, forming a large amount of bilirubin. It is this bilirubin that causes the skin to take on a yellowish color.

2. A newborn's liver is immature and cannot process bilirubin as quickly as he will be able to when he gets older. This slow processing of bilirubin has nothing to do with liver disease. It merely means that the baby's liver is not as fully developed as it will be, and thus, there is some delay in eliminating the bilirubin.

Physiologic jaundice:
Most babies with jaundice have physiologic jaundice. This is the type of jaundice that is caused because of the natural process of breaking down red blood cells.

Other factors:
Occasionally there are other factors that cause jaundice in an infant. Two of these causes are conditions known as ABO Incompatibility and Rh Incompatibility. Both of these conditions result in a very fast breakdown of red blood cells. Also, jaundice may appear in infants with physical defects in the organs that work to eliminate bilirubin from the body. If the baby's jaundice is caused by either of these (or other) conditions, expect additional details from the doctor or nurse caring for the baby.

What happens when a newborn baby has jaundice?
Physiologic jaundice is usually seen around the second or third day of life. The nurse or doctor caring for the baby will notice it and may request a blood test. Based on the results of the test and based on the general condition of the baby, the doctor will decide whether treatment should be started. If no treatment is felt necessary, the jaundice will usually decrease after a week and disappear within two weeks. If treatment is required, commonly a Bililight is used. This treatment is also known as phototherapy. Another name for the light is a Bilirubin Reduction Light.

What is a Bililight and why is it used?
A Bililight consists of a series of fluorescent lights that are placed over the baby's bed. The light helps the baby to get rid of bilirubin found just beneath the surface of the skin. It does this by changing the structure of the bilirubin, thereby making it easier to be excreted by the liver.

How is the Bililight used? How long is it used?
The Bililight is placed over the baby's bed, which will be either an Isolette or a radiant warmer bed. The baby is undressed to provide maximum skin exposure; the baby's skin will not darken or burn under this light. The baby may be under the light for several days. Laboratory tests and physical appearance guide the doctor in his evaluation of the baby's progress. The light will be discontinued at the earliest possible time.

How is the baby cared for during phototherapy?
Masks are placed over the baby's eyes to prevent exposure to the bright light. The baby's position is changed frequently to assure that all areas of the baby's skin are exposed to light and also to assure the baby's comfort. The baby may be fed under the light or may be taken out for the feedings, according to the doctor's instructions.

How do babies tolerate the light?
Each baby is an individual and, thus, unique in his response to this treatment. Some babies are very fussy because they miss being wrapped tightly in their blankets. Other babies sleep very contentedly.

While under the light, the baby usually has frequent and loose bowel movements. In some circumstances, his stools are greenish in color. This is temporary and should stop when treatment is discontinued.

The medical staff at the hospital knows that you are concerned about your baby and realizes that having your baby underneath the lights limits your contact with the baby. Remember, this treatment lasts only a few days. In no time at all, you and your baby will be ready to go home.

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All babies develop elevated serum bilirubin (SBR) levels, to a greater or lesser degree, in the first week of life. This is due to increased production (accelerated red blood cell breakdown), decreased removal (transient liver enzyme insufficiency), and increased reabsorption (enterohepatic circulation). For example, using Gartner's data 1 , the mean SBR for normal babies during the first week is represented by the blue line in the graph below.

However, when a baby does become jaundiced, a common dilemma is deciding at what SBR level to intervene. The decision is influenced by whether the baby is term or preterm, well or sick, and the presence or absence of blood factors predisposing to hyperbilirubinaemia.

Incidence and risk factors:

Virtually all babies have a transient rise in SBR, but only about 50% are visibly jaundiced. This varies with race, those of asian background having a higher incidence.

It is clinically useful to classify jaundice according to the age of the baby when he/she becomes visibly jaundiced.

Early (days 1-2) - uncommon
Haemolytic jaundice (Rhesus, ABO, others)

Normal (days 3-10) - very common
Uncomplicated
Complicated - see below

Late (days 14+)
Breast milk - common
Conjugated jaundice - uncommon
Inherited deficiency of glucuronyl transferase enzymes - very rare

Factors likely to make physiological jaundice worse in a given baby include:

prematurity
bruising
cephalohematoma
polycythaemia
delayed passage of meconium
breast feeding
certain ethnic groups, esp Chinese

Consequences:

Severe jaundice

Definition of severe jaundice depends on the clinical setting:
Uncomplicated term babies >450
Babies with haemolytic jaundice - see jaundice - haemolytic
Preterm babies - depends on gestational age - see below

Kernicterus (bilirubin encephalopathy). This clinical syndrome includes hypertonia progressing to opthistotonia, seizures, and may lead to death. At autopsy, such babies display evidence of bilirubin staining of the basal gangia.

Late sequelae to kernicterus. These include sensorineural hearing impairment and cerebral palsy, often with ataxia and chorioathetosis.

Once a baby develops severe jaundice, the risk of progressing to kernicterus is increased by the following:

acidosis
drugs which displace bilirubin from albumin (esp. sulphonamides and related compounds)
hypoalbuminaemia
The late effects of moderate levels of jaundice on extremely preterm infants is unknown, although it is generally accepted they are more at risk than term infants for the same SBR level.

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Breast Milk Jaundice

This occurs infrequently, peaks in the 2nd or 3rd week, and may persist at moderately high levels for 3-4 weeks before declining slowly. It is a diagnosis of exclusion. In an otherwise well infant, it is considered a benign condition. If feeding with breast milk is stopped, the serum bilirubin usually falls, however this would very rarely be indicated. The potential harms of stopping breast feeding would outweigh any risks of a mild or moderate hyperbilirubinaemia. The aetiology is unknown, but there is some support for both a hormonal factor in the milk acting on the infant's hepatic metabolism, and an enzyme (lipase) facilitating intestinal absorption of bilirubin.

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University of Iowa Family Practice Handbook, Fourth Edition, Chapter 12

Pediatrics: Neonatal Jaundice
Heidi Koch and Mark A. Graber, MD
Departments of Pediatrics, Family Medicine, and Emergency Medicine
University of Iowa College of Medicine
Peer Review Status: Externally Peer Reviewed by Mosby

Jaundice is visible when a baby has a serum bilirubin level that exceeds 5 mg/dl. Generally jaundice is visible first on the head and progresses to the feet. It resolves with the opposite pattern, the feet clearing first.

Physiologic Hyperbilirubinemia.

Usually not present in first 24 hours.
Rarely increases by more than 5 mg/dl in 1 day.
Peaks at 48 to 72 hours in full-term infants and 4 to 5 days in the premature ones.
Serum bilirubin does not exceed 13 mg/dl in the full-term infant and 15 mg/dl in the preterm infant.
Direct bilirubin fraction is generally <2 mg/dl.
Physiologic jaundice disappears by 1 week in full-term infants and by 2 weeks in premature infants.
Any infant that does not meet the above description has nonphysiologic hyperbilirubinemia and should be worked up.

Nonphysiologic Hyperbilirubinemia.

Those with primarily elevated direct bilirubin. Direct bilirubin >15% of total and therefore conjugated by the liver.
Infections including sepsis, perinatally acquired viral infections including hepatitis, and intrauterine viral infections (hepatitis B, TORCHS).
Metabolic abnormalities including Rotor syndrome and Dubin-Johnson syndrome, alpha-1 antitrypsin deficiency, galactosemia, tyrosinosis, cystic fibrosis, hereditary fructose deficiency.
Anatomic abnormalities, including biliary atresia and Alagille syndrome (ductopenia) and obstructions as with a choledochal cyst.
Cholestasis from CVN/TPN, antibiotics (especially ceftriaxone).

Those with primarily elevated indirect bilirubin. Therefore not conjugated by liver.

Two basic mechanisms:

From increased production of bilirubin (therefore hemolysis or hematoma breakdown).
With positive direct Coombs’ test (mother’s antibodies on child’s cells). Isoimmunization (Rh, ABO, minor blood group), erythro-blastosis fetalis.
With negative Coombs’ test and RBC morphologic abnormalities. Spherocytosis, thalassemias, G6PD deficiency, elliptocytosis, etc.
Extravascular blood. Cephalohematoma, severe bruising, cerebral and pulmonary hemorrhage
DIC, other hemolytic anemia
Polycythemia resulting from delayed clamping of cord, twin-twin transfusion, maternal-fetal transfusion.

From delayed excretion of bilirubin.
Inherited disorders of bilirubin metabolism including Crigler-Najjar syndrome, Gilbert’s disease, Dubin-Johnson syndrome, Rotor syndrome.
Hypothyroidism and prematurity.

Breast Milk Jaundice.

General. One in every 200 infants has prolonged unconjugated hyperbilirubinemia. Serum bilirubin may reach maximum concentration (15 to 25 mg/dl) during the second to third week. Etiology is unknown.

However, one theory is that there is a component in breast milk which can interfere with bilirubin conjugation. Kernicterus has not been reported with breast milk jaundice.

Diagnosis. Requires the exclusion of all other causes of elevated unconjugated bilirubin in a breast-fed infant.

Treatment options:
(1) Observe,
(2) Discontinue breast feeding and substitute formula,
(3) Alternate feedings of breast milk and formula,
(4) Discontinue breast feeding and start phototherapy, and
(5) Continue breast feeding and start phototherapy.

Comment on therapy.
Although any treatment option is reasonable, it is believed that any interruption of breast feeding is undesirable un- less very severe hyperbilirubinemia is present (TSB >25). Observe, and continue breast feeding while phototherapy is initiated.

Treatment of hyperbilirubinemia from any cause. (Table 12-1).

Treat the underlying disorder.

Ensure adequate hydration, caloric intake, stooling (bilirubin is excreted in stool).

Prophylactic phototherapy.
Indicated for infants showing a rapid rise in bilirubin (>1 mg/dl per hour) and as a temporizing measure when one is contemplating exchange transfusion.
Conjugated bilirubin does not cause kernicterus.
Phototherapy. The number of banks of phototherapy lights used is determined by the infants total bilirubin level, the rate of rise of the total bilirubin, and the anticipated course of the underlying cause of the hyperbilirubinemia. Serum bilirubin usually decreases by 2.5 to 3 mg/dl per day and 1-2 mg/dl in first 4-6 hours of phototherapy. Bilirubin level should be followed every 12 hours. Phototherapy should be discontinued when the bilirubin reaches levels of about 13 mg/dl. Bilirubin levels should be rechecked again 12 hours after discontinuation, to assess for recurrence.